1. Field
The present application relates generally to wireless communications, and more specifically to systems and methods for performing transmit power control.
2. Background
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) represents a major advance in cellular technology and is the next step forward in cellular 3G services as a natural evolution of Global System for Mobile communications (GSM) and Universal Mobile Telecommunications System (UMTS). LTE, in some instances referred to as Release-8 of 3GPP, provides for an uplink speed of up to 50 megabits per second (Mbps) and a downlink speed of up to 100 Mbps and brings many technical benefits to cellular networks. LTE is designed to meet carrier needs for high-speed data and media transport as well as high-capacity voice support. Bandwidth is scalable from 1.25 MHz to 20 MHz. This suits the needs of different network operators that have different bandwidth allocations, and also allows operators to provide different services based on spectrum. LTE is also expected to improve spectral efficiency in 3G networks, allowing carriers to provide more data and voice services over a given bandwidth. LTE encompasses high-speed data, multimedia unicast and multimedia broadcast services.
The LTE physical layer (PHY) is a highly efficient means of conveying both data and control information between an evolved NodeB (eNB) and mobile access terminals (ATs) or user equipment (UE). The LTE PHY employs some advanced technologies that are new to cellular applications. These include Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) data transmission. In addition, the LTE PHY uses Orthogonal Frequency Division Multiple Access (OFDMA) on the downlink (DL) and Single Carrier-Frequency Division Multiple Access (SC-FDMA) on the uplink (UL). OFDMA allows data to be directed to or from multiple users on a subcarrier-by-subcarrier basis for a specified number of symbol periods.
Overload indication is one aspect LTE, wherein an eNB measures uplink Interference over Thermal (IoT) noise. If the IoT noise is above a certain threshold, then an event is triggered where an overload indication message is sent to the eNBs of neighboring cells via a wired backhaul network (e.g., an X2 interface or the like). However, instances may occur when a given node or terminal is not capable of receiving such overload indication messages from neighboring nodes via the wired backhaul network (e.g., when the backhaul network is down). Accordingly, it would be desirable to deliver the overload indication message as an Over-The-Air (OTA) broadcast. Moreover, it would be desirable to encode the overload indication message to include both coarse and finer resolution data regarding the measured interference.